LITERARY NOTICLS. 305 



Buckland ; Secretaries, W, Sanders, S. Stuchbury, T. J. Torrie, and F. H. 

 Rankin, Esquires. 



D. ZOOLOGY AND BOTANY. (At Colston* School) President, Prof. Hens- 

 low ; Secretaries, John Curtis, and S. Rootsey, Esquires, Prof. Don, and Dr. 

 Riley. 



E. ANATOMY AND MEDICINE, (At Colston's School) President, Dr. 

 Roget ; Secretaries, Dr. Symonds, and G. D. Fripp, Esq. 



F. STATISTICS. (At the Cathedral Chapter-room) President, Sir C. Lemon; 

 Secretaries, Rev. J. E. Bromby, C. B. Frepp, and J. Heywood, Esquires. 



G. MECHANICAL SCIENCE. (At the Merchants' Hall) President, Davies 

 Gilbert, Esq. ; Secretaries, T. G. Bunt, G. T. Clark, and W. West, Esqrs. 

 In all the sections, papers of very great interest have been read. In section 



A. Sir D. Brewster gave some account of an experiment made by him in mak- 

 ing lenses of rock-salt. Mr. Lubbock made statements respecting the com- 

 parative tides of London and Liverpool, and on the influence of atmospheric 

 pressure as affecting tides ; and he was followed by Mr. Whewell on the same 

 subject, and also on theCommittee's proceedings for ascertaining the relative level 

 of the sea and land with respect to its permanence. These remarks are so im- 

 portant that we venture to lay some of them before our readers. 



It is intended to appoint a committee for the same purposes, who should be 

 furnished with instructions founded upon the views at which the former Com- 

 mittee had by their labours and experience arrived. One method proposed 

 was that marks should be made along various parts of the coast, which marks 

 should be referred to the level of the sea; but here the enquiry met us in the 

 very outset what is the proper and precise notion to be attached to the phrase 

 level of the sea ? Was it high water-mark or low water-mark ? Was it at the 

 level of the mean tide, which recent researches seemed to establish ? In com- 

 posing hydrographical maps the level of the sea was taken from low water, and 

 this, although in many respects inconvenient, could not yet be dispensed with, 

 for many reasons, one of which he might glance at that, by its adoption, 

 shoals, which were dry at low water, were capable of being represented upon 

 the maps as well as the land. The second method proposed appeared to be 

 the one from which the most important and conclusive results were to be ex- 

 pected. It consisted in accurately levelling, by land survey, lines in various 

 directions, and by permanently fixing, in various places, numerous marks of 

 similar levels at the time ; by the aid of these marks, at future periods, it could 

 be ascertained whether or not the levels had or had not changed, and thus the 

 question would be settled whether or not the land was rising or falling. Still 

 further, by running on those lines as far as the sea-coast, and marking their 

 extremities along the coast, a solution would at length be obtained to that most 

 important question what is the permanent level of the sea at a given place ? 

 Until something like this were accomplished, we could not expect any thing 

 like accuracy in many important and even practical cases. As an example, he 

 supposed the question to be the altitude of Dunbury Hill referring to the level 

 of the sea : if that level of the sea were taken at Bristol, where the tide rises 

 fifty feet, the level of low water would differ from the same level on the sea- 

 coast at Devonshire, where the sea rises, say eighteen feet ; and supposing the 

 *place of mean tide tobe the true permanent level by no less a quantity than six- 

 teen feet, which would therefore make that hill to appear sixteen feet higher, 

 upon an hydrographical map constructed by a person taking his level from 

 the coast of Devonshire, than it would appear upon the map of an engineer 

 taking his level at Bristol. In the method proposed, the lines of equal level 

 would run, suppose from Bristol to Ilfracomb in one direction, and from Bris- 

 tol to Lime Regis in the other, and by these a common standard of level would 

 soon be obtained for the entire coast. 



Mr. G. B. Gerrard's researches on the general solution, which were reported 

 by Sir William Hamilton, attracted great interest in the section, and elicited 

 some very high eulogies from Prof. Peacock and Mr. Babbage on Mr. Jerrard's 



